The American Academy of Ophthalmology – the world's largest association of eye physicians and surgeons – is reminding the public that it does not recommend marijuana or other cannabis products for the treatment of glaucoma.
Based on analysis by the National Eye Institute and the Institute of Medicine, the Academy finds no scientific evidence that marijuana is an effective long-term treatment for glaucoma, particularly when compared to the wide variety of prescription medication and surgical treatments available. Ophthalmologists also caution that marijuana has side effects which could further endanger the user's eye health.
Primary open-angle glaucoma (POAG), the most common form of glaucoma and a leading cause of blindness in the United States, occurs when tissue in the eye gradually becomes less efficient at draining fluid. As this happens, eye pressure (called intraocular pressure or IOP) rises, causing irreparable damage to the optic nerve.
Initial studies in the 1970s reported that smoking marijuana or administering it orally or intravenously (but not topically applied to the eye) did lower IOP for 3 to 4 hours, but there is no evidence to date that proves it alters the long-term course of the disease. Glaucoma medication and surgical treatments – which are scientifically proven to be effective and safe for daily use – also do not have the negative side effects of marijuana.
In addition, marijuana lowers blood pressure throughout the body, resulting in the potential to lower the blood flow to the optic nerve which can lead to vision loss. This could effectively cancel out the benefit of a lowered IOP. In addition to the commonly known side effects of marijuana, people who smoke marijuana also increase their risk for cancer and eye diseases.
People who have glaucoma and are considering using marijuana to treat the disease are strongly urged to consult an ophthalmologist about the risks.
"Ophthalmologists are focused on providing treatments that will give patients the very best results," said Gregory L. Skuta, MD, glaucoma specialist and president of the American Academy of Ophthalmology. "For glaucoma, this means recommending therapies that have been proven to safely alter the course disease over a long-term period, such as medicated eye drops or surgery. No research exists to date that demonstrates that marijuana can deliver this level of efficacy."